Some research studies suggest that massages can help in improving your fitness by:

1. Improving Circulation and Nutrition of Muscles
Vital nutrients must be pumped back into the muscle after exercising to help it increase in size. Massages get the blood flowing so it can carry these nutrients to the muscles.

2. Shortening recovery time between workouts.
Lactic acid increases in the muscles through working out and increased circulation through massage will help the blood carry the acid out of the muscles and elimiate toxins.

Basically, massages help improve circulation which aids in getting the bads stuff out while helping the good stuff flow into the muscles. So you can recover quicker and endure tough workouts more frequently.